As hardware for reproducing and storing high resolution or high quality video content is being developed and supplied, a need for a video codec for effectively encoding or decoding the high resolution or high quality video content is increasing. According to a conventional video codec, a video is encoded according to a limited encoding method based on a macroblock having a predetermined size.
Image data of a spatial domain is transformed into coefficients of a frequency domain via frequency transformation. According to a video codec, an image is split into blocks having a predetermined size, discrete cosine transformation (DCT) is performed on each block, and frequency coefficients are encoded in block units, for rapid calculation of frequency transformation. Compared with image data of a spatial domain, coefficients of a frequency domain are easily compressed. In particular, since an image pixel value of a spatial domain is expressed according to a prediction error via inter prediction or intra prediction of a video codec, when frequency transformation is performed on the prediction error, a large amount of data may be transformed to 0. An amount of data of an image may be reduced by replacing data that is consecutively and repeatedly generated with small-sized data.
A multi-view video codec encodes and decodes a base-view image and one or more dependent-view images. The base-view image and the one or more dependent-view images respectively include a texture picture and a depth picture corresponding to a view. An amount of data of a multi-view image may be reduced in such a manner that redundancy of the base-view image and the one or more dependent-view images and redundancy between the texture picture and the depth picture are removed.
A depth image is an image indicating the distance between a viewpoint and an object and is used to synthesize texture images from certain viewpoints. The depth image is invisible to humans, similarly to a texture image, and thus it is difficult for humans to recognize distortion of the depth image.
Generally, an encoding method having high coding efficiency has a high distortion rate. Thus, an encoding method having a distortion rate which is recognizable to humans is not generally used even when this method has high coding efficiency. However, since distortion of a depth image is difficult for humans to recognize, a multi-view image may be encoded using an encoding method having high coding efficiency to increase overall coding efficiency. Accordingly, an encoding method having higher coding efficiency than coding efficiency of a method of encoding a texture image may be suggested as a method of encoding a depth image.